This study deals with the estimation method for effective transverse elastic moduli in fiber reinforced composite having circular-arc shaped interfacial cracks. The effective moduli can be obtained if we compute the change of the potential energy due to the inhomogeneities (i.e. the fibers) and the interfacial cracks.
The change of the potential energy due to the interfacial cracks is obtained by using its relation to the L integral. The L integral, which has the path-independent property, is computed from the known solution of the stress intensity factors $K_I$＆$K_{II}$ by Perlman and Sih. The change of the potential energy due to the fibers is evaluated by various methods such as the Mori-Tanaka method, Self-Consistent method, Generalized Self-Consistent method and Differential Scheme.
The results with the various method mentioned above are compared and it is found that all the method mentioned above yield approximately the same results up to the volume fraction of fiber, f = 0.2. The Mori-Tanaka method and Differential Scheme seem to give the same results for the crack angle below about 60 degrees when the volume fraction of fiber, f is larger than 0.2, while they yield the results different from those based on the Self-Consistent method and Generalized Self-Consistent method. It seems likely that the effect of reinforcement is lost in fiber reinforced composite when the crack angle gets larger than 60 degrees.
